About the Expedition

The R/V Knorr sets sail from the capital city of the Azores, Porta Delgada, on June 10, 2010 with researcher Lloyd Keigwin, his science team, the crew of the R/V Knorr and three teachers from Massachusetts.  This research cruise will take them all the way across the North Atlantic back to R/V/ Knorr’s homeport at Woods Hole Oceanographic Institution (WHOI) over the course of three weeks.

Keigwin is a Senior Scientist at WHOI interested in climate and ocean history. This is also known as paleoclimatology. Just as humans can read books and newspaper articles that document events in the past, nature has ways of communicating information about Earth’s climate past too! In order to learn about our Earth’s climate and ocean history, Keigwin uses climate proxies, which are sources of climate information from nature. Corals, fossil pollens, tree rings and ice cores are examples of climate proxies.  Keigwin isn’t traveling to Antarctica to sample ice, nor is he cutting into trees to see their rings.  The part of the ocean he will be looking in doesn’t have corals. Instead, Keigwin is using tiny, shelled organisms that lived in the ocean hundreds of thousands of years ago to help him piece together sections of the climate puzzle. He’s looking for foraminifera (“forams”). Where will he be able to find them?

At the bottom of the ocean!

On this cruise, Keigwin and his team will be traveling by ship out to specific spots in the North Atlantic Ocean to pull sediments up from the ocean floor. These sediments are rich with forams.  There are two main groups of forams:  benthic and planktonic. Keigwin is primarily interested in planktonic foraminifera called “Globigerinoides ruber”  ("G.ruber”).

When forams die, their soft organic matter is decomposed and recycled into the biochemical system of the upper ocean. Their shells, however, fall down through the water column to the bottom of the ocean. Millions of tiny foram shells accumulate on the ocean floor, and there they are preserved in the ocean sediment. So when Keigwin and his team pull forams up from the ocean floor, they’re pulling up fossils.   These fossils are extremely interesting and helpful for researchers. They act like a “snapshot” of what the Earth’s climate was like when they were alive! And because they live in specific ocean environments, they can tell researchers a great deal about what the oceans were like when the forams were alive.

G.Ruber live close to the surface of the ocean (top 25 meters), high in the water column. These forams make their shells from oxygen, carbon, calcium and other ions in the ocean water.  For paleoclimate research, it’s the oxygen in these shells that is particularly helpful. Some oxygen atoms are “heavier”  (O-18) than others.  “Light” oxygen (O-16) gets trapped in ice on Earth’s surface. So when Earth has a lot of ice (glaciers, sea ice), there is less light oxygen available to earth systems. That leaves lots of “heavy” oxygen available in the earth’s system and it makes its way into oceans where forams are making their shells. It’s not ONLY heavy oxygen in the oceans at these times – there’s simply more heavy oxygen available when Earth has more ice.  When scientists study the oxygen present in forams, they are determining ration of O-18 to O-16.   The higher the O-18, the more ice on Earth, which indicates a cooler global climate. The lower the O-18, the less ice on Earth, which indicates a warmer climate.  Scientists can get a very good idea of how much ice was on the planet at the time that the forams lived, which indicates the climate of the past – paleoclimatology!

Forams are found everywhere in the ocean! They have been around in the oceans for hundreds of millions of years!

Check out this site for images of different types of forams!By the end of the cruise, Keigwin and his team will have lots of recovered ocean sediments that they will store in WHOI’s “core repository” at the Seafloor Samples Lab. There, the sediments will be available to other researchers when Keigwin is done with them. Hopefully Keigwin will also have paleoclimate information that he can share with the world’s scientific community!